Managing Without Emtryl

Joint NGO/GFA Advice December 2004

Introduction

These notes have been prepared jointly by the National Gamekeepers’ Organisation (NGO) and the Game Farmers’ Association (GFA) to assist game rearers, game keepers, agents, owners and others to manage without Emtryl from 2003 onwards.

They summarise the advice given during numerous NGO and GFA meetings held during November and December 2002, at which veterinarians, feed compounders, keepers and game farmers discussed the issues and the possible ways ahead.

Decisions on whether to rear and release without Emtryl, and if so how, must rest with individuals. Our role is to provide the information for you to take into account when making those decisions in the light of your particular circumstances. One thing must be made very clear at the start, however…

All the vets agree that unless individuals give careful consideration to their future rearing and releasing without Emtryl, there will be animal welfare problems and widespread economic consequences.

‘Managing Without Emtryl’ is therefore a carefully chosen title for these notes. We will manage but only if the management of our rearing / releasing systems is modified.

Background

Emtryl (chemical name dimetridazole or DMZ) has been generally used in UK game rearing for over 30 years. It was first introduced to control blackhead but has since been used mainly to prevent and cure hexamitiasis and trichmoniasis. These two protozoal infections are very common and their consequences are made worse by the birds being stressed in any way. Infected flocks can suffer over 80% mortality, although the precise mechanisms of death and disease transmission are still not fully understood. The use of Emtryl prophylactically in the feed, and as a treatment in the drinking water, have become commonplace and have allowed the game industry to rear on a scale that may well be unsustainable without Emtryl. Now that Emtryl has gone, the industry therefore urgently needs to consider management changes.

Why Emtryl has gone

DMZ was implicated as a carcinogen in rats many years ago, prompting fears that it could be dangerous to use in animals destined for human consumption. Although the trials were inconclusive, Governments all over the world have progressively restricted the use of DMZ. It was withdrawn as a veterinary medicinal product throughout the EU in 1996, except for the UK where a licence was maintained for using DMZ in gamebirds. Use as a medicinal feed additive was stopped in the EU in May 2002, when the product was withdrawn for regulatory reasons. The EU has now called the UK Government to task for failing to ban DMZ, and at the same time the UK Food Standards Agency has told our Government that more tests would be needed to ensure human safety. Merial, the sole UK distributor of Emtryl has withdrawn sales and said that no more Emtryl will be sold unless and until the licensing arrangements can be cleared up. Most commentators believe that this is unlikely ever to happen.

Current legal situation

Currently, the UK product licences for Emtryl remain in place, so existing supplies of Merial’s Emtryl, legally distributed in the UK before the withdrawal of the products during 2002, can be used up under appropriate veterinary prescription. The use of any other form of DMZ, whether obtained in this country or from overseas is illegal. Both the Veterinary Medicines Directorate and HM Customs and Excise are on the alert, actively looking for illegal drug imports and misuse. If they detect illegalities, and the UK product licence is rescinded as a result, it would then become an offence to use even the remaining stocks of Merial’s Emtryl.

Alternatives to Emtryl

Many of those attending our meetings have asked if there is an alternative to Emtryl in the pipeline. The answer is no. There are no similar compounds, nor is there any likelihood of any drug company spending the millions of pounds necessary to get a new compound developed and licensed on the off-chance of making a comparatively modest return from the UK game industry alone.

Drugs used in America for treating blackhead would be illegal here, with no realistic chance of their being specially licensed. Arsenic products used in France are likewise illegal here. Anti-biotics (eg. tetracyclines) provide one route for treating the bacterial outbreaks which may be associated with hexamita but the problems of antibiotic resistance must be borne in mind.

Some people have claimed success with herbal products and essential oils. These may indeed help but always be aware that unscrupulous people are likely to be trying to cash in on the disappearance of Emtryl by selling you all sorts of unproven products.

In the absence of Emtryl and any clear alternative(s), the industry’s main attention must therefore turn to the management of the gamebirds. The rest of this document is designed to do just that.

Emtryl-free Gamebird Management

All gamebirds have parasites within them. It is only when the parasite numbers build up in birds with little immunity that disease and death can follow. Fit gamebirds in low-stress environments can and do survive challenge by hexamita and trichomonads.

In the future, therefore, right through from day old chick to young adulthood, our birds are going to need to have everything in their favour: best possible diet, copious clean water, thoroughly hygienic huts and pens, prevention and cure of other diseases that can weaken them and lower their immunity, and – above all - minimal stress.

The main causes of stress in gamebird rearing and releasing are:

Handling
Transporting
Lack of good food (also unfamiliar foods/unfamiliar feeders)
Dehydration
Chilling (and draughts)
Overheating
Stale air
Disease and parasites
Social factors (overcrowding and aggression)
Predator presence / predator attacks

In planning to manage without Emtryl, all the above factors need to be carefully considered. Good gamebird management should aim to avoid any combination of more than one of these stress-inducing factors at any one time.

So your Emtryl-free management plan should start with a re-assessment of the numbers to be reared and the equipment required.

1. Numbers and densities

High densities of birds assist disease spread and increase stress during rearing / releasing. Consider your plans in the light of the following:

Many game farmers are planning to cut back production by 25 to 33%
Some shoots are already investing in new equipment and larger pens
Most vets don’t advise more than 300 birds in an 8’ X 8’ hut – preferring approximately 4-5 square feet per poult to 6 or 7 weeks of age
The Game Conservancy Trust advise no more than 300 birds per acre of release pen (700 birds per hectare of release pen)
Many shoots have more birds than their huts/pens were designed for
Reducing densities does not necessarily mean lower overall production (for example, some pig breeders have reduced their stocking densities but increased output pro rata because disease levels have fallen significantly)

2. Equipment audit

When you start to go through your equipment needs, ask yourself the following:

Is your rearing/releasing equipment all top quality?
Have all egg-washers, setters and hatchers been serviced?
Are the huts clean? (Creosote used well in advance and allowed to dry thoroughly is an excellent disinfectant)
Are the brooder lamps reliable, with good temperature control?
Have you excluded draughts whilst ensuring good ventilation?
Is the water system adequate? (see Nipple Drinkers, page 8)
Are there plenty of feeders to avoid competition.
Are feeders of a type that cannot be contaminated by the birds’ faeces?
Are the feeders/drinkers of the same type throughout rearing/release, to ensure familiarity and reduce growth checks and stress?
Are transport crates airy, cleaned between batches (a legal requirement) and properly sheltered during transit?
…and so on… Go though your entire system looking for weak points

3. Management audit

You also need to think through all your gamebird management activities:

Assess your previous disease history and what can be learned from it.
Have a clear management programme for addressing other common diseases (eg rotavirus, coccidiosis)
Locate huts and pens on clean, free-draining ground, ideally not used within the previous three years.
Could laying/ hatching/ rearing be separated, even having separate staff? (Mechanical spread from old to young birds is a very common problem)
Are you taking a risk by using the same equipment more than once? (If so, what steps are you taking to reduce the risk?)
Ensure all staff are briefed on the risks and properly trained. You may be able to involve your vet in this process.
Increase your biosecurity (Think: correct detergents and disinfectants/ disposable clothing/ gloves/ footdips/changes of footwear, etc.)
Will visitors/pets be banned from the rearing/releasing areas?
Can your egg washing / sanitization be improved? (eg collecting more regularly and from drier laying areas)
Ensure you are prepared for deliveries (eggs/chicks and poults)
Ensure water lines are cleaned, sanitized and checked regularly
Reduce feed changes to the minimum. Ensure you have amino acids (eg fishmeal) in your starter ration.
Are drinkers/feeders off the ground, on wire and regularly disinfected?
Is there any weakness in your system that freely allows birds to re-ingest the faeces? This is a major source of disease problems.
Will you be doing routine post-mortems to monitor flock health?
Will your entire rearing programme be fully recorded and analysed?
Write down your Emtryl-free management plan

4. Releasing audit

The following suggestions will help everyone involved in releasing poults:

If you have no Emtryl to use up, make sure any bought-in poults have been reared Emtryl-free, or you are likely to have real disease problems
Reduce your risk by buying from only one source
Could you release in better ways? Some shoots are trying trickle release or even rearing within the release areas.
Will vet’s advice be sought at the planning stage? (eg. a pen inspection)
Will you be buying local poults? (Locally sourced poults will have more relevant immunities, be spared the stress of a long journey and can be delivered at a time when the weather is suitable for releasing)
Will liaison between game farm, shoot and vet be closer than ever?
Discuss what financial guarantees your supplier is prepared to make.
Consider rotating pens, with fallow years, and fencing off wet areas.
Are the pens in top condition, providing a varied, quality habitat?
Is there plenty of sunlight in the pens for poults to dry and warm up? (Sunlight is also an excellent, free disinfectant)
Will the feeders/drinkers be the same as on the game farm? (see above)
Pens must be ready, with feed/water and predator exclusion in place before any birds arrive. Do not work on/within pens just after delivery.
Check journey times are legal on the papers accompanying deliveries.
Use skilled labour to unload poults and ensure good access to pens.
Ensure the poults are on the same feed after delivery as before
Will you have no more than 300 birds per acre / 700 birds per hectare of release pen? (The Game Conservancy Trust’s recommendation)
Will biosecurity be better than ever? (no visitors/fresh foot dips)
Vermin presence and attacks can cause huge stress. Predator control and good quality cover within the pens are therefore very important.
Do you have to wing clip? Clipping necessitates extra handling. Unclipped birds get out and away from trouble quicker, reducing the stocking density in the pen. (About 50% of people no longer clip wings).
Tagging your birds can help to track disease issues

Because rearing and releasing systems vary so much, the above advice cannot be specific. We can only give you an idea of the sorts of things you should be thinking about. Life after Emtryl is not about hoping, against the odds, that nothing will go wrong. It is going to require a lot of forethought, changes and, not least, a lot more money. Most game farmers are putting up their poult prices because of the extra costs they feel they must incur in order to rear safely without Emtryl. Other game rearers should expect to see their expenditure rise too. No-one can afford to cut their costs.

If you want to rear/release safely without Emtryl, only the best will do.

Other points:

Several other points arose during our many meetings that may be helpful to you:

Breeder health

Fit birds survive better, so paying attention to the origin of your eggs/chicks/poults is now more important than ever. Do you know if the parent birds were fit? Was there a proper strategy to control mycoplasma in the breeding flock? Is the laying environment clean and healthy? Are the eggs collected quickly and washed correctly? If the birds are your own, you can of course make sure.

Rearing on concrete

Although in the UK there is a strong tradition of grass-reared poults, the poultry industry has shown over many years that disease control is easier in birds reared on concrete. Concrete allows the droppings and therefore much disease risk to be washed away. Bedding can be kept drier and temperature controlled better. This is a complex subject and one on which you may well need to seek the advice of vets and game rearers who have already tried. There can be downsides in terms of acclimatization to the wild but some rearers are definitely planning to keep their birds on concrete for longer.

Rearing on wire

Some rearers are also considering rearing pheasants on wire, as is common on the continent. This often seems to give a couple of seasons of trouble-free rearing but the set-up costs are high. There could also be PR implications worth considering. The main benefit is that all the droppings fall away, reducing the risk of re-infection.

Nipple drinkers

There is general agreement that water quality is a much-neglected factor in gamebird rearing. Too many types of drinker allow birds to walk through their water. Slow-moving, warm water is a haven for breeding bacteria. Products such as hydrogen peroxide and chlorine should be used. Nipple drinkers reduce water contamination, disease, spillages and overcrowding. Whatever the drinking system used, it must be flushed regularly. Would you drink from it yourself? If not, don’t use it for your birds!

Acidic guts

Many vets believe that keeping the pH of the bird’s gut slightly acidic helps the bird to fight disease. This is something to discuss with your vet. Several feed companies are looking to add more organic acids to their foods in the future.

Antbiotics

Anti-biotics can be used to kill out the pathogens in the gut a couple of days before any necessary management processes which might involve stress.

Pro biotics

Pro biotics promote the development/re-development of a protective gut flora, which helps the bird to fight against dangerous pathogens.

Electrolytes

Electrolytes promote hydration of newly hatched chicks and re-hydration of young birds after stress inducing events. They are cheap to use. Ask your vet’s advice.

We hope these notes have helped. Think hard, act now and GOOD LUCK.

Published December 2002 by the National Gamekeepers’ Organisation and the Game Farmers’ Association.

We would like to thank the many professionals, veterinarians and others, who have assisted at our meetings with keepers and game farmers to discuss managing without Emtryl, and without whom these notes would not have been possible. In the interest of the whole shooting industry, these notes may be copied, providing due acknowledgement is made to the NGO and the GFA.

National Gamekeepers’ Organisation
PO Box 107
Bishop Auckland
DL14 9YW
Tel/Fax: 01388 665889
www.nationalgamekeepers.org.uk

Game Farmers’ Association
Colnbrook
Withington
Cheltenham
GL54 4BW
Tel/Fax: 01242 890372